Sewing machine



Jan. 29, 1935. c. w. MUELLER SEWING MACHINE Filed NOV. 18, 1932 6Sheets-Sheet 1 6. Mae/k7 Jan. 29, 1935. c. w. MUELLER SEWING MACHINEFiled Nov. 18, 1932' '6 sheets sheet 2 gwuc/wfom c. n Mae fler- Jan. 29,1935. I c, w, MUELLER 1,989,602

- SEWING MACHINE Filed Nov. 18, 1932 6 Sheets-Sheet 3 awuem/bom C. W.Mae/A97" Jan. 29, 1935. c. w. MUELLER SEWING MACHINE Filed Nov. 18, 1932e Sheets-Sheet 4 C. W. MUELLER SEWING MACHINE Jan. 29, 1935.

, Filed Nov. 18, .1932 s Sheets-Shet 5' I 3mm Gin. Mae/let W Jan. 29,1935. c. w. MUELLER 1,939,602

' 1 SEWING MACHINE Filed Nov. 18, 1952 6 Sheets-Sheet 6 CM Nae/fier- IPatented Jan. 29, 1935 SEWING MACHINE Charles w. Mueller, St. Louis,Mo., assignor to Lewis Invisible Stitch Machine Company, St. Louis, Mo.,a corporation of Maine Application November 18, 1932, Serial No. 643,283

22 Claims.

This invention relates to new and useful improvements in sewing machinesgenerally, although more particularly to sewing machines of the blindstitch type.

Among the several objects of the invention are to provide a blind stitchsewing machine for use in felling or hemming operations; to provide astitch forming mechanism for forming a line of lock stitches, and toprovide an oscillatory ridge forming means for presenting a ridge ofmaterial into needle penetrating position, the ridge forming'meanspresenting both the base layer and the fell or hem to the needle oncertain reciprocations thereof to form resultant anchor stitches andpresenting the hem or upper layer only to the needle on intermediatereciprocations thereof to form resultant skip stitches;

to providesuch a machine with a bottom feeding mechanism and a topfeeding mechanism, which 2 are arranged in proper cooperative relationwhereby the fell or hem will be properly fed; to provide means foroscillating the ridge forming device from the main shaft and to providemeans for imparting'the backward and forward travel to the lower feeddog from said ridge forming means, and to provide a supplementary workclamp connected to the vertically reciprocatory main work clamp forcooperation with the stationary presser foot to clamp the body fabrictherebetween and thereby firmly retain said body fabric not only againstthe thrust of the needle but also against the return movement of thelower feed.

With these and other objects in view which will more fully appear, thenature of the invention will be more clearly understood by following thedescription, the appended claims, and the several views illustrated inthe accompanying drawings.

In the drawings:

Figure 1 is a top plan view of a machine constructed in accordance withmy invention, parts being shown in section, V t

Figure 2 is a left hand elevation thereof,

Figure 3 is a front elevation of the machine, parts being shown insection,

Figure 4 is a detail elevation showing particularly the gear andeccentric driving connections for the ridge'forming disc,

Figure 5 is a detail section showing the connection between theeccentric sleeve driving disc and the associated gear,

Figure 6 is an elevation of said driving disc,

Figure '7 is an elevation showing the ridge forming disc in one extremeposition relative to the needle path, together with nections for saiddisc,

Figure 8 is a similar view but showing the disc in its other extremeposition relative to the needle path, I Figure 9 is a top plan view ofthe presser foot, theridge forming disc, the needle, the lower feed dog,and the upper feed dog,

Figure 10 is a cross sectional view showing more or lessdiagrammatically the position of 10 the needle, the ridge forming disc,and the material when the needle ispenetrating both the base layer andthe hem,

Figure 11 is a similar view but showing the parts when the needle is.penetrating the hem only,

Figure 12 is a perspective view of" the ridge forming disc, the partsbeing shown in separated relation,

Figure 13 is a top plan view of the main work clamp, the supplementalwork clamp, the lower feed dog, and the ridge forming disc,

Figure 14 is a side elevation of the main work clamp showing thesupplemental work clamp attached thereto, and

Figure 15 is a perspective viewshowing the main work clamp and thesupplemental work clamp in separated relation.

Referring to the accompanying drawings, my improved sewing machineincludes a frame comprising a base 5 having a hollow standard 6 risingfrom the rear right hand corner thereof and having a pair of posts '7, 8projecting upwardly and located in front of said standard. Extendinglaterally towards the left from the upper end of the standard is ahorizontal arm 9, and extending forwardly from the left hand end thereofto a point in advance of the posts 7, 8 is an arm 10. A stationarypresser foot 11 is attached to the front end of the arm 10. A worksupport or plate 12 is pivoted on the posts '7, 8 through the medium ofa bearing rod 13 mounted in said posts and the left hand end of saidplate is disposed below the presser foot 11. A spring 14 functions toyieldably urge the work plate upwardly towards the foot, and the upwardmovement is adjustably limited by a depending arm 15 which is rigid withthe table and a cooperating adjustable stop 16 mounted on the base.

Journaled in the horizontal arm 9 is a main rotary shaft 17 whichthrough the usual connections 18 oscillates a needle shaft 19 which isjournaled in the forwardly extending arm 10. Fixed to the forward end ofthe needle rock shaft 19 is a curved needle 20 whichoscillates directlythe driving conabove the presser foot and in a path transverse to thelongitudinal axis thereof, the forward or work penetrating stroke beingfrom left to right.

Cooperating with the needle 20 to form a series of lock stitches is arotary hook 21 which is fixed to a shaft 22 journaled in a bearing lug23 extending forwardly from the front end of the frame arm 10, the hookshaft 22 being disposed in parallelism with the main shaft 17. The hookshaft 22 is rotated from the main shaft 1'7 through the medium of anintermediate or cross shaft 24 which has its forwardend journaled in thebearing lug 23 and its rear end journaled in a bearing 25 on thehorizontal arm 9. A 2-to-1 gear coupling 26 connects the main shaft 17with the rear end of the cross shaft 24 and a 1-to-1 gear coupling 2'7connects the front end-of the cross shaft 24 with p the hook shaft 22,thus providing a driving connection between the main shaft and the hookshaft which causes the hook to be rotated twice to each revolution ofthe main shaft.

As previously stated, this machine is particularly adapted for fellingoperations or for hemming operations, and to this end means are-providedfor projecting a ridge of material upwardly through the foot into needlepenetrating position during each cycle of operation. The presser foot 11is formed with 'a longitudinal opening 28 through which-the ridge ofmaterial is projected by an oscillatory finger or disc 29. The disc 29is fixed to a rock shaft 30 journaled in bearings depending from thework support 12, the shaft being disposed in parallelism with the mainshaft 17. The rock shaft 30 is oscillated from the main shaft throughthe medium of the following connections. A driving eccentric 31 is fixedto the main shaft, and surrounding this eccentric is an eccentric sleeve32 which is positively rotated on the eccentric but at one-half thespeed thereof. A disc 33 which is loosely mounted on the main shaft 17is provided with a radial slot 34 for receiving a slide block 35 fixedto the eccentric sleeve 32 by a shank 36 and a lock screw 3'7 whichcooperates with the shank. A driving gear 38 is fixed to the main shaftand rotatable on a stationary shaft 39 mounted in the frame standard 6is a reduction gear unit including a large gear 40 and a smaller gear41, the former being in constant mesh with the driving gear 38, and thelatter being in constant mesh with a gear 42 fixed to the disc 33. Thegear coupling ratio is such that the eccentric sleeve-32 is rotated onceduring every two revolutions of the main shaft 17. In order to rock thedisc supporting shaft 30 from the eccentric 31 and eccentric sleeve 32,I have jou'rnaleda rock shaft 43 insuitable bearings depending from thework support 12 and extending in parallelism with the main shaft 17. Arock arm 44 which is clamped to the rock shaft 43 is connected by-a link45 to a rock arm 46 clamped to the disc supporting shaft- 30. Alsoclamped to the rock shaft 43 is an actuating rock arm 47 having alongitudinally extending slot 48. A strap link 49 has one end fittingaround the eccentric sleeve 32, and the other end adjustably connectedto the arm 4'7 throughthe medium of a clamp screw 50 which passes intothe slot 48,

This ridge forming disc 29 is quadrant shaped and includes aridgeforming concentric surface or portion 51 and a radial rear edge 52which joins said surface 53. The extent of oscillation of the disc 29 isconstant regardless of the fact that both the eccentric 31 and theeccentric sleeve 32 control the movements of the strap link 49. Theeccentric 31 functions to oscillate the disc 29 between two fixed radialpoints, the rear point relative to the needle path being shown by theposition of the comer 53 of the disc in Figure '7. The eccentric sleeve32, which rotates once to every two revolutions of the eccentric 31,functions to vary the position of the angular range of the oscillatorymovement of the disc,29, the rear point relative to the needle pathbeing shown by the position of the corner 53 of the disc in Figure 8. Itwill be noted that in the Figure '7 position, the corner 53 of the discis in front 'of the needle path whereas in Figure 8'the corner is inrear thereof. It will also be noted that the corner in Figure .8 ishigher. relative to the horizontal point of needle penetration than itis in Figure 7 thereby insuring the needle penetrating both the baselayer A and the hem or fell B but only the hem in the Figure '7position, these conditions being clearly disclosed in Figs. 10 and 11.

By reference to the line X-X in Figure 8, it will be noted that theshank 36 is about 25 below the center line and therefore when theeccentric 32 is in this position, the ridge forming disc 29 is in aposition to insure the needle penetrating the base layer and the hem asshown in Figure 10. It will also be noted that in Figure '7 the shank 36has been moved from the Figure 8 position, although the drivingeccentric 31 is in the same position as shown in Figure 8, but due tothe ratio of the 2-to-1 gearing and to the position of the sleeveeccentric 32, the position of the angular range of movement of the ridgeforming disc 29 has been moved to the needle center line-and thereforethe base layer will not be lifted a distance sufficient to receive theneedle and the latter will enter the fell or hem only as shown in Figure11. Attached to the ridge forming disc 29 is a finger 54. This finger isU-shaped and includes attaching arms 55, 55 and a nose 56 which projectsupwardly from the connecting ends of the arms. These arms are arcuateand are arranged in concentric relation to the disc supporting shaft 30.Clamping screws 5'7, 58 pass through suitable openings in the arms 55and through openings 59 and 60 in the ridge forming disc 29. Thediameter of the opening 60 through which the screw 58 passes has adiameter greater peripheral portions arranged in tandem and of stitches,and in another extreme angular position ofthe disc the low peripheralportion 56 will be presented to the needle and the latter will penetratethe hem only to form resultant "skip stitches. Thus the high and lowperipheral portions of the disc cooperate with the needle toperiodically vary the depth of the needle penetrationin the work.

It will thus be noted that the ridge formm' g disc 29 is oscillated fora fixed distance and that the position of oscillation of the disc isbodily shifted during successive oscillations thereof.

Cooperating with the bottom of the presser foot 11 is a main work clamp61 which is rigidly attached to the upper end of a post' 62 which ismounted in the work plate 12 for vertical reciprocations.

A lower 4-motion feed dog 63 operates through feed slots 64, 65 whichare formed in the work cations to the work-clamp 61 and also the up anddown movements to the feed dog 63, I have J'ournaled a rock shaft 66 insuitable bearings dependingfrom the-work plate .12. This shaft. isrocked from the main shaft 19 through suitable.

connections indicated generally at 67. The rock shaft 66 is provided atone end with a crank arm 68 carrying a crank pin 69 which is engaged byone end of a lift lever 70, the other end of the lever being pivotallyconnected as at 71 to the lower end of the post 62. The feed dog 63 ispivotally connected to the upper end of a substantially verticallydisposed link 72, the lower end of said link being pivotally connectedto the lift lever 70. Thus when the feed dog 63 is lifted In order toimpart back and forth movements.

into engagement with the stationary foot 11, the work clamp 61 will belowered, and vice versa.

of commercial hemmer may be either mounted,

on the presser foot or on the work plate as is readily understood bythose skilled in the art. It will also be understood that either asingle fold'hem or a double fold hem may be employed.

When the work is fed through the machine the hem as well as the baselayer immediately under the hem will be formed into a ridge which willbe projected upwardly through the opening 28 in the presser foot 11 bythe high portion 51 of the ridge forming disc 29. It will be observedthat there will be either two or three thicknesses of fabric, dependingon the nature of the hem being formed, disposed between the bottom ofthe presser foot 11 and the top of the main work clamp 61, thesethicknesses being located on the right hand side of the disc 29 asviewed in Figures and 11 and on that side of the disc opposite the pointof needle penetration. Thus it will be seen that the base layer A is ofbut a single thiclmess and is located between the bottom of the presserfoot and the left hand side of the work clamp and therefore this baselayer is not clamped but is free to move. Consequently the ridge formedby the disc 29 will not beheld taut to receive the needle thrust, andneither will said layer be clamped against the foot to resist thedragging action of the feed dog during the return movement thereof. Inorder to overcome these objections, I have mounted a supplementaryworkclamp 75 on the main work clamp,

61 and on that side of the main clamp directly under the singlethickness or body fabric A. This supplemental clamp 75 is pivotallymounted at its lower end as at 76 on the upper end of an arm 77 which ispivoted as at 78 to the side wall of a recess formed in the left side ofthe'main work clamp 61. Stop shoulders 79, 80 respectively formed on themain and auxiliary clamps cooperate to limit the pivotal movement of thesupplemental clamp relative to the main clamp, and a stop shoulder 81formed on the main work clamp 61 cooperateswith the upper end of the arm77 to limit the upward movement thereof. A flat spring 82 is secured tothe under side of the main clamp 61 and the free end of this springextends under the arm 77 and functions to press 'said arm upwardlywhereby the supplemental clamp 75 will be yieldingly retained inengagement with the bottom of the presser foot 11. Thus by pivotingthesupplemental work clamp 75 on the arm 77, said clamp willautomatically parallel itself with the bottom of the presser foot 11-regardless .of. the vertical position of reciprocation of the'main workclamp 61.

Although, I have disclosed and described a 2-to-1 gear coupling 26 forrotating the hook twice to each revolutionofthe' main shaft, it

will be understood that the ratio of these gears may be changed ifdesired, and when making such a change it will be only necessary toretime the sleeve 32 in relation to the eccentric 31 as will be readilyunderstood by those skilled in the art.

From the foregoing, it will be readily understood that when a hemmingoperation is being performed the ridge forming disc 29 will project aridge of material upwardly through the opening 28 in the presser foot 11and into needle penetrating position; that in one extremerearwardposition of the disc 29 the needle will enter and emerge through boththe body fabric A and the hem B and form resultant anchor stitches,whereas in thealternate extreme rearward positions of the disc 29, theneedle will enter and emerge through the hem B only and form resultantskip stitches; that by means of the finger 54 which is adjustablymounted on the ridge forming disc 29 the machine may be readily adjustedto compensate for different thick-.

nesses of materials; that by connecting the lower feed dog with the rockshaft which oscillates the ridge forming disc, I have eliminated a lineof driving connections to the main shaft, and that I have provided asupplementary work clamp for cooperation with the bottom of the presserfoot to clamp the base layer against the foot and thereby not onlyretain said base layer against the needle thrust but also prevent saidbase layer from being dragged by the feed-dog during the backwardmovement thereof.

It will be also apparent that the disc 29 and finger 54 cooperate toform peripheral surfaces arranged in tandem and of different radii; thatthe finger 54 forms a peripheral recess at the forward edge 52 of thedisc; that the disc is oscillated in timed relation to the needlereciprocations to successively position the peripheral portion 51 andthe peripheral recess in register with the needle path of travel to varythe effective-depth of needle penetration, whereby the needle willpenetrate all the layers of the fabric when the peripheral portion 51 ofthe of the" disc is in register with, the path of needle travel an forma resultant skip stitch; that layer or layers only when the peripheralrecess I the action of the main driving connections between the mainrotary shaft 17 and the oscillatory disc shaft is modified by theinclusion of the eccentric 32 which is positively rotated by a reductiongear coupling 38, 40, 41, 42 to effect the periodic change in theangular position of the disc; and that the finger 54 which forms thebottom of the peripheral recess, supports the fabric layers against thethrust of the needle when said skip stitches are being formed.

It is of course to be uderstood that the details of structure andarrangement of parts may be variously changed and modified withoutdeparting from the spirit and scope of my invention.

I claim:

1. In a blind stitch sewing machine,'an oscillatory ridge-forming disc,means for angularly oscillating said disc for a fixed amount, and meansfor varying the position of the angular range of movement of said discduring alternate oscillations thereof. a

2. In a blind stitch sewing machine, an oscillatory ridge-forming disc,means for angularly oscillating said disc for a fixed amount, and meansfor varying the position of the angular range of movement of said discduring alternate oscillations thereof including a driving eccentric, aneccentric sleeve surrounding the eccentric,

and a reduction gear coupling between the eccentric and the sleeve.-

3. In a blind stitch sewing machine, an oscillatory ridge-forming disc,means for angularly oscillating said disc for a fixed amount, and meansfor varying the position of the angularrange of movement of said discduring alternate oscillations thereof comprising a rock shaft supportingthe disc, a main rotary shaft, an eccentric fixed to the mainshaft, aneccentric sleeve surrounding said eccentric, driving connections betweenthe eccentric sleeveand the rock shaft, and a reduction gear couplingbetween the main shaft and the eccentric sleeve.

4. In a blind stitch sewing machine for felling or hemming, thecombination with a stationary presser foot having an opening, of astitch forming mechanism located above the foot and including areciprocatory needle having its path of movement across the opening insaid foot,

an oscillatory ridge forming disc mounted below.

the foot for projecting a, ridge of hemmed material upwardly through theopening in the foot into needle penetrating position, means forangularly oscillating the disc for a fixed'amount, and means for varyingthe position of the angular range of movement of the disc duringalternate oscillations thereof toinsure the needle pene-" cluding areciprocatory needle having its path of movement across the opening insaid foot,

an oscillatory ridge forming disc mounted below the foot for projectinga ridge of materialupwardly through the opening in the foot into needlepenetrating position, means for angularly oscillating the disc for afixed amount, .and' means for varying theposition of the angular rahgeof movement of the disc during alternate oscillations thereof to insurethe needle penetrating the hem only during alternate strokes andpenetrating both the body fabric and the hem during intermediatestrokes, said shifting means comprising a driving eccentric, aneccentric sleeve surrounding the eccentric, and a reduction gearcoupling between the eccentric and the sleeve. f

6. In a'blind stitch sewing machine for felling or hemming, thecombination with a stationary presser foot having an opening, of astitch forming mechanism located above the foot and including areciprocatory needle having its path of movement across the opening insaid foot, an oscillatory ridge forming disc mounted below the foot forprojecting a ridge of material upwardly through the opening in the footinto needle penetrating position, means for angularly oscillating thedisc for a fixed amount, and means for varying the position of theangular range of movement of the disc during alternate oscillationsthereof to insure the needle penetrating the hem only during alternatestrokes and penetrating both the bodyfabric and the hem duringintermediate. strokes, said shifting means comprising a rock shaftsupporting the said eccentric, driving connections between the eccentricsleeve and the rock shaft, andareduction gear coupling'between the mainshaft and the eccentric sleeve.

'1. In a blind stitch sewing machine, the combination with a frameincluding a standard, of an arm extending laterally therefrom, an armextending forwardly from said laterally extending arm, a .depressiblework plate disposed in front ofathe'laterally extending arm, a presserfoot fixed to the frJnt end of the forwardly extending arm and disposedabove one end of the work plate, said foot havingan opening, a mainshaft journaled in the overhanging arm, an oscillatory needle shaftjournaled in the forwardly extending arm, a curved needle fixed to theforward end of said needle shaft, driving connections between the mainshaft and the needle shaft, a rotary hook shaft journaled inthe frontend of the forwardly extending arm, a hook fixed to said shaft, drivingconnections between the main shaft and'the hook shaft, means mounted onthe work plate for projecting a ridge of material upwardly through theopening in the foot into needle penetrating position, a verticallyreciprocatory work clamp mounted on the work plateand cooperating withthe bottom of the foot to clamp the work against the thrust of theneedle, and afeed mechanism for intermittently feeding the work past theneedle.

. 8. In a blind stitch sewing machine, the combination with a frameincluding a standard, of an arm extending laterally therefrom, an armextending forwardly from said laterally extend ing arm, a depressiblework plate disposed in front of the laterally extending arm, a presserfootfixed to the front end of the forwardly extending arm and disposedaboveone end of the work plate, said foot having an opening, a mainshaft journaled in the overhanging arm, an oscillatory needle shaftjournaled in the forwardly extending arm, a curved needle fixed to theforward end of said needle shaft, driving connections between the mainshaft and the needle shaft, a rotary hook shaft journaled in the frontend of the forwardly extending arm, a hook fixed to said shaft, drivingconnections between the main shaft and the hook shaft \comprising adriving shaft, a 1-to-1 gear coupling between the driving shaft and thehook shaft, and a 2-to-1 gear the opening in the foot into needlepenetrating position, a vertically reciprocatory work clamp mounted onthe work plate and cooperating with the bottom of the foot to cl'ampthework against the thrust of the needle, and a feed mechanism forintermittently feeding the work past the needle.

9. In a blind stitch sewing machine for felling or hemming,th ecombination with a frame including a standard, of an arm extendinglaterally therefrom, an arm extending forwardly from said laterallyextending arm, a depressible work plate disposed in front of thelaterally extending arm, a presser foot fixed to the front end of theforwardly extending arm and disposed above one end of the work plate,said foot having an opening, amain shaft journaled in the overhangingarm, a stitch forming mechanism mounted on the front end of theforwardly extending arm and including a reciprocatory needle having itspath of movement across the opening in the presser foot, means forreciprocating the needle from the main shaft, a rock shaft journaled onthe depressible work plate and extending under said foot, said rockshaft being disposed in parallelism with the main shaft, an oscillatorydisc fixed to said rock shaft for projecting a ridge of materialupwardly through the opening in the foot into needle penetratingposition, and operating connections between the main shaft and the rockshaft for oscillating the disc for a fixed amount and for varying theposition of the angular range of movement of forwardly extending arm anddisposed above one end of the work plate, said foot having an opening, amain shaft journaled in the overhanging arm, a stitch forming mechanismmounted on the front' end of the forwardly extending arm and including areciprocatory needle having its path of movement across the opening inthe presser foot, means for reciprocating the needle from the mainshaft, a rock shaft journaled on the depressible work plate andextending under said foot, said rock shaft being disposed in parallelismwith the main shaft, an oscillatory disc fixed to said rock shaft forprojecting a ridge of material upwardly through the opening in the footinto needle penetrating position, and operating connections between themain shaft and the rock shaft for oscillating the disc for a fixedamount and for varying the position of the angular range 'of movement ofthe disc during alternate oscillations thereof to insure the needlepenetrating the hem only during alternate strokes and penetrating boththe body fabric and the hem during intermediate strokes, said operatingconnections comprising an'eccentric fixed to the main shaft,

an eccentric sleeve surrounding said eccentric,

driving connections between the eccentric sleeve and the rock shaft, anda reduction gear coupling 11. In a blind stitch sewing machine, anoscillatory ridge-forming disc having a concentric ridge-engaging edge,and aridge-engaging finger mounted on said disc for fixed adjustmentstowards and from said edge.

12. In a blind stitch sewing machine, an oscillatory ridge-forming dischaving a concentric ridge-engaging edge and a radially extending forwardedge merging with'the concentric edge, a ridge-engaging finger pivotedon said disc and provided with a nose located beyond the radial forwardedge of the disc, and means for clamping the finger in any position ofpivotal adjustment.

13. In a blind stitch sewing machine, the combination with a frame, of astationary presser foot secured thereto and provided with an opening, a

stitch forming mechanism located above the foot and including areciprocatory needle having its path of movement across the openinginthe foot, a main shaft, an oscillatory shaft disposed below the foot andoperated from the main shaft, a disc fixed to the oscillatory shaft forprojecting a ridge of material upwardly through the presser foot openinginto needle penetrating position, a 4- motion lower feed dog cooperatingwith the bottom of the foot for intermittently feeding the work past theneedle, and means for imparting back and forth movements and up and downmovements to the feed dog including'connections between the dog and thedisc supporting shaft for imparting back and forth movements to the dogand other connections between the dog and the main shaft for imparting.up and down movements to the dog.

14. In a blind stitch sewing machine for felling or hemming, thecombination with a horizontal stationary presser foot having an opening,of a stitch forming mechanism located above the foot and includingareciprocatory needle having its path of movement across said opening,means for intermittently projecting the base fabric and the superposedhem upwardly through said opening into needle penetrating position,means including a 4-motion feed dog for feeding the work past theneedle, a vertically reciprocatory main work clamp for clamping the hemagainst the bottom of the foot during the return movements of the feeddog and during needle penetrating movements, and an upwardly springpressed supplemental work clamp mounted on the main work clamp forclamping the body fabric against the bottom of the foot to therebyretain said body fabric against being dragged by the feed dog during itsreturn movement and to retain the fabric stationary against the thrustof the needle.

between the main shaft and the eccentric sleeve.

15. In a blind stitch sewing machine, a staridge formingelement. a 16.In a blind stitch sewing machine, a stationary presser foot, avertically reciprocatory main work clamp cooperating with the bottom ofthe foot, an arm pivoted at one end to the main work clamp, asupplemental work clamp pivotedto the free end of said arm forcooperation with the bottom of the foot, and a spring connected to themain clamp and bearing against said arm for pressing the arm and thesupplemental clamp upwardly.

17. In a blind stitch sewing machine, a stationary presser foot, avertically reciprocatory main work clamp cooperating with the bottom ofthe foot, an arm pivoted at one end to the main work clamp, asupplemental work clamp pivoted to the free end of said arm forcooperation with the bottom of the foot, a spring connected to the mainclamp and bearing against said arm for pressing the arm and thesupplemental clamp upwardly, and cooperating means between said clampsto limit the pivotal movement of the supplemental clamp.

18. Ina blind stitch sewing machine, a sta-,

tionary presser foot, a vertically reciprocatory main work clampcooperating with the bottom of the foot, an arm pivoted at one end tothe main workclamp, a supplemental work clamp pivoted to the free end ofsaid. arm for cooperation with the bottom of the foot, a springconnected to the main clamp and bearing against said arm for pressingthe arm and the supplemental clamp upwardly, and cooperative meansbetween said clamps to limit the pivotal movement of the arm.

19. In a blind stitch sewing machine, an oscillatory ridge-forming disc,means for angularly oscillating said disc, and means for varying theposition of the angular range of movement of said disc during successiveoscillations thereof.

20. In a blind stitch sewing machine, an oscillatory ridge-forming dischaving high and low peripheral portions arranged in tandem,.areciprocatory needle, means for reciprocating the needle transversely ofthe disc, and means for oscillating the disc in timed relation to thereciprocations of the needle to thereby present said disc portionsperiodically to the needle to vary the effective depths of the needlepenetrations.

21. In a sewing machine, the combination with a main shaft, of anoscillatory shaft, a ridgeforming disc fixed thereto and havingperipheral surfaces of different radii arranged in tandem, a needlereciprocating above the disc, and'driving connections between saidshafts for periodically presenting to the needle first one'of saidsurfaces of the disc and then the other to thereby vary the effectivedepths of the needle penetrations.

22. In a sewing machine, the combination with a main shaft, of anoscillatory shaft, a ridgeforming disc fixed thereto and havingperipheral surfaces of 'difierent radii arranged in tandem, a needlereciprocating above the disc, and driving connections between saidshafts for periodically presenting to the needle first one of saidsurfaces of the disc and then the other to thereby vary the effectivedepths of the needle penetrations, said driving connections including areduction gear and an eccentric driven thereby.

CHARLES W. MUELLER.

